Monolithic integration of group III nitride epitaxial layers

Abstract

A monolithically integrated device includes a substrate, a first set of Group III nitride epitaxial layers grown for a first HFET on a first region of the substrate, and a second set of Group III nitride epitaxial layers for a second HFET grown on a second region of the substrate.

What is claimed is: 
     
       1. A monolithically integrated device comprising:
 a substrate; 
 a first set of Group III nitride epitaxial layers grown on a first region of the substrate for a first heterostructure field effect transistor; and 
 a second set of Group III nitride epitaxial layers grown on a second region of the substrate for a second heterostructure field effect transistor; 
 wherein the first set of epitaxial layers comprises an AlN barrier layer; 
 wherein the second set of epitaxial layers comprises an AlGaN barrier layer; 
 wherein the first heterostructure field effect transistor comprises a low noise amplifier; and 
 wherein the second heterostructure field effect transistor comprises a power amplifier. 
 
     
     
       2. The monolithically integrated device of  claim 1  wherein:
 the first set of Group III nitride epitaxial layers comprise AlN, GaN, or InN or any combination of AlN, GaN, or InN; and 
 the second set of Group III nitride epitaxial layers comprise AlN, GaN, or InN or any combination of AlN, GaN, or InN. 
 
     
     
       3. The monolithically integrated device of  claim 1  wherein:
 the first heterostructure field effect transistor is an enhancement mode device; and 
 the second heterostructure field effect transistor is a depletion mode device. 
 
     
     
       4. The monolithically integrated device of  claim 1 :
 wherein the first set of epitaxial layers comprises a first AlGaN layer on the substrate, a first GaN layer on the first AlGaN layer, and the AlN barrier layer on the first GaN layer; and 
 wherein the second set of epitaxial layers comprises a second AlGaN layer on the substrate, a second GaN layer on the second AlGaN layer, and the AlGaN barrier layer on the second GaN layer. 
 
     
     
       5. The monolithically integrated device of  claim 4  further comprising:
 a third GaN layer on the AlN barrier layer. 
 
     
     
       6. The monolithically integrated device of  claim 4 :
 wherein the first AlGaN layer comprises an Al 0.08 Ga 0.96 N layer. 
 
     
     
       7. The monolithically integrated device of  claim 4 :
 wherein the second AlGaN layer comprises an Al 0.04 Ga 0.96 N layer.